Armored attachment plug with selfcentering cord clamp and strain relief



I/llllllllllfl vfflfllflllll S. M. WEISBERG ARMORED ATTACHMENT PLUG WITH SELF-CENTERING Filed June 15, 1951 CORD CLAMP AND STRAIN RELIEF 'Qrllllllf'flillll! June 21, 1955 ARMORED ATTAQHMENT PLUG WITH SELF- ggNTEFRlNG (JORD CLAMP AND STRAIN LIE Sidney M. Weisberg, Newark, N. 3., assignor to Allied Electric Products, 1nd, Irvington, N. J., a corporation oi New Jersey Application June 13, 1951, Serial No. 231,310

1 Claim. (Cl. 339-103) The invention here disclosed relates to attachment plugs of the armored type and the general objects of the invention are to provide a plug of this character of rugged, strong construction but relatively small in size so as to be usable in many places where space is limited.

Special objects of the invention are to provide simple, practical means for automatically centering and clamping the cord and in a manner to transfer load or pull on the cord to the armored casing of the plug.

Other important objects of the invention are to pro vide a plug having the advantages mentioned, which will consist of but few parts and be capable of production at low cost.

The foregoing and other desirable objects are attained by the novel features of construction, combination and relation of parts, as hereinafter set forth and as illustrated U in the accompanying drawing.

in this drawing there is shown a practical commercial embodiment of the invention but structure may be modified and changed within the true intent and scope of the invention as hereinafter defined and claimed.

Pig. 1 in the drawing is a substantially central sectional view of one of the new plugs, with the cord clamped in place and shown broken away at the bottom;

Fig. 2 is a broken sectional view on a plane at right angles to the first View, substantially as on line 2--2 of Fig. 1;

Fig. 3 is a view of the blade end of the plug;

Fig. 4 is a view ofthe cord clamp end of the plug.

In the several views the plug body is shown as a narrow, substantially parallel-sided piece of insulating material 5 carrying projecting contact blades 6 at one end and having a passage 7 for the cord 8 extending from that end out through the opposite end.

The armor is shown as a shell 9 shaped to closely fit about the base and confined thereto by having the edge at the open end of the same flanged inwardly at 10 over the beveled edge portion 11 of the base.

The cord clamp consists of a pair of opposed clamping plates 12 secured together by clamp screws 13 and having inclined extensions 14 slidingly confined between the convergently inclined end faces 15 of the base and the correspondingly inclined parallel spaced end walls 16 of the armor shell.

In the present disclosure the inclined slide guiding faces 15 are shown as grooveways depressed in the end of the plug body so as to provide flanges 17 along opposite edges for guiding the slides and for spacing the inclined end walls 16 of the cover at a proper distance not to bind the slides immovably against the end of the base.

The armor has an opening 18 in the end of the same wide and long enough to freely pass the projecting shank portions of the cord clamp plates and to permit free sliding adjustment of the inclined extensions 14 as these plates are set up into firm clamping engagement'with the cord. v

When the screws 13 are loosenedthe clamp plates 12 2,711,521 Patented June 21, 1955 may be separated as much as need be to freely pass the cord.

Then, after the wire ends have been secured by the binding screws 19 the clamp screws 13 may be tightened without regard to centering the cord, for the clamp plates "ice will automatically center themselves as they are drawn together by sliding over the inclined end faces of the base, as confined in this relation by the enclosing shell. With the cord fully clamped any strain on the cord is taken up by the clamp plates and transferred by them to the armor shell and base structure.

The plug consists of but few parts and can be made of 1 small size without sacrificing strength and durability. The parts are readily assembled and the plug as a whole can be produced at low cost. The convergently inclined end of the plug improves the appearance as well as keeping down the external dimensions of the plug.

In addition to automatically centering the cord clamp, the matching inclines on the end of the plug body and the clamp plates have the eiiect of locking the clamp in the centered position, preventing the clamp from shifting or being pulled to one side or the other.

In further carrying out the purposes or" the invention, the contact blades are shown as doubled on themselves at 29 to form anchorage portions, and these doubled portions split at 21 for spreading in the base block and the bent back portions extended laterally to form the terminal lugs 22 for the binding screws.

Also, the base is shown as having openings 23 extending entirely therethrough' to receive the doubled, split anchorage portions 29. The outer ends of through openings 23 are shown widened in Fig. 2 to provide shoulders 24 over which the doubled split end portions of the blades are bent to positively lock the blades in place.

The widened, outer ends 25 of the blade receiving passages or seats provide ample space for entry of a suitable tool for spreading the split, doubled inner ends of the blades to, in effect, rivet the blades in their seated position in the base.

The laterally extended terminal lugs aid in solidly locating the blades in seated relation and provide abutments for holding the blades at the front while the split portions are spread at the back of the base.

After securing the blades by spreading the split inner ends of the same, the cavities left may be filled in over the spread ends of the blades with suitable insulating material 26.

Similarly, the cavities 27 in the front of the base for receiving the binding screws may be filled in about the screws from the back of the base through molded openings 28. The filling of insulating material 29 about the screws further aids in securing the parts together.

What is claimed is:

Armored attachment plug as disclosed and comprising a thin, flat plug body having a central cord passage therethrough from end to end and blade and terminal passages therethrough lined up at opposite sides of the cord passage, contact blades and terminals at one end of the plug body located in said passages at the sides of the central cord passage, the opposite end of the plug body being convergently inclined toward the central cord passage and having flat, shallow, convergently inclined channels therein open to the ends of the blade and terminal passages andbounded at opposite sides of the plug body by projecting side flanges, the ends of the blade and terminal passages being open to said inclined channels, and plugs of insulating material in said ends of the blade and terminal passages electrically separating said passages from the inclined guide channels, companion cord clamping plates having inclined feet slidingly engaged in said inclined guide channels between said side flanges and overlying said-insulating plugs in the ends of the contact and terminal passages, an armor shell enclosing said base and haying conyergently inclined end wallsengaged over, said side flanges of'the base and spaced thereby from the inclined channels in the end of the plug body to overlie and slidingly, confine the inclined feet portions of the clamp plates and screw means for sliding the clamp plates together in centered relation over the end of the plug body. 7

References Cited in the file of this patent UNITED STATES PATENTS Roberts May 8, Shoe June 12, Hubbell Aug. 7, Webster Dec. 6, Tregoning Dec. 5, Kollath Nov; 27, Gunthorp Oct. 20,

Von Holtz May 21, 

